Xh. He et al., CHARACTERIZATION OF BEET YELLOWS CLOSTEROVIRUS-SPECIFIC RNAS IN INFECTED PLANTS AND PROTOPLASTS, Phytopathology, 87(3), 1997, pp. 347-352
Tetragonia expansa plants infected with a California isolate of beet y
ellows virus (BYV-60) contained multiple BYV-specific RNAs identified
by Northern blot hybridization. These RNAs were identified by cDNA pro
bes specific to six open reading frames (ORFs). One genomic RNA and fi
ve subgenomic (sg) RNAs representing the p65/p6.4, p64, p24, p22, and
p21 ORFs were identified. A probe derived from the 3'-terminal ORF (p2
1) hybridized to each of the sgRNAs, indicating the RNAs are 3' coterm
inal. Hybridization with 5'- and 3'-end probes indicated that preparat
ions of BYV particles contained the genomic RNA as well as two additio
nal RNA molecules corresponding in size to the coat protein (CP) sgRNA
and an unidentified RNA. A Chenopodium quinoa protoplast system also
was used to study BYV replication. The temporal accumulation of BYV-sp
ecific RNAs and CP was investigated in protoplasts transfected with pu
rified virion RNA. Accumulation of genomic plus-strand RNA was evident
as early as 15 h postinoculation. The development of this protoplast
system is significant for studies of closterovirus replication.